391935677897 has 8 divisors (see below), whose sum is σ = 398483630376. Its totient is φ = 385419589632.

The previous prime is 391935677893. The next prime is 391935677899. The reversal of 391935677897 is 798776539193.

It can be written as a sum of positive squares in 4 ways, for example, as 70615621696 + 321320056201 = 265736^2 + 566851^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391935677897 - 2² = 391935677893 is a prime.

It is a super-2 number, since 2×391935677897² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (391935677891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7941248 + ... + 7990449.

It is an arithmetic number, because the mean of its divisors is an integer number (49810453797).

Almost surely, 2^391935677897 is an apocalyptic number.

It is an amenable number.

391935677897 is a deficient number, since it is larger than the sum of its proper divisors (6547952479).

391935677897 is a wasteful number, since it uses less digits than its factorization.

391935677897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15932107.

The product of its digits is 540101520, while the sum is 74.

The spelling of 391935677897 in words is "three hundred ninety-one billion, nine hundred thirty-five million, six hundred seventy-seven thousand, eight hundred ninety-seven".